Make python and yaml FSMs eqvivalent so it's a nice example

solvable/src/event_handler_main.py

@@ -3,6 +3,7 @@ from functools import partial
 
 from tornado.ioloop import IOLoop
 
+from tfw import YamlFSM
 from tfw.components import IdeEventHandler, TerminalEventHandler
 from tfw.components import ProcessManagingEventHandler, BashMonitor
 from tfw.components import TerminalCommands, LogMonitoringEventHandler
@@ -80,10 +81,9 @@ class TestCommands(TerminalCommands):
 
 
 if __name__ == '__main__':
-    FiveStepTestFSM = partial(TestFSM, 5)
     fsm = FSMManagingEventHandler( # TFW FSM
         key='fsm',
-        fsm_type=FiveStepTestFSM
+        fsm_type=partial(YamlFSM, 'test_fsm.yml')
     )
     ide = IdeEventHandler(  # Web IDE backend
         key='ide',
@@ -105,7 +105,7 @@ if __name__ == '__main__':
         process_name='webservice',
         log_tail=2000
     )
-    eventhandlers = {ide, terminal, processmanager, logmonitor, fsm}
+    eventhandlers = {fsm, ide, terminal, processmanager, logmonitor}
 
     commands = TestCommands(bashrc=f'/home/{TAOENV.USER}/.bashrc')
     terminal.historymonitor.subscribe_callback(commands.callback)

solvable/src/test_fsm.py

@@ -1,3 +1,7 @@
+# This defines an FSM equvivalent to test_fsm.yml
+
+from os.path import exists
+
 from tfw import LinearFSM
 from tfw.networking import MessageSender
 
@@ -5,24 +9,29 @@ from tfw.networking import MessageSender
 class TestFSM(LinearFSM):
     # pylint: disable=unused-argument
 
-    def __init__(self, number_of_steps):
+    def __init__(self):
-        super().__init__(number_of_steps)
+        super().__init__(6)
         self.message_sender = MessageSender()
+        self.subscribe_predicate('step_3', self.step_3_allowed)
+
+    @staticmethod
+    def step_3_allowed():
+        return exists('/home/user/workdir/allow_step_3')
 
     def on_enter_1(self, event_data):
-        self.state_notify(1)
+        self.message_sender.send('FSM', 'Entered state 1!')
 
     def on_enter_2(self, event_data):
-        self.state_notify(2)
+        filename = '/home/user/workdir/cat.txt'
+        with open(filename, 'w') as ofile:
+            ofile.write('As you can see it is possible to write arbitrary python code here.')
+        self.message_sender.send('FSM', f'Entered state 2! Written stuff to {filename}')
 
     def on_enter_3(self, event_data):
-        self.state_notify(3)
+        self.message_sender.send('FSM', 'Entered state 3!')
 
     def on_enter_4(self, event_data):
-        self.state_notify(4)
+        self.message_sender.send('FSM', 'Entered state 4!')
 
     def on_enter_5(self, event_data):
-        self.state_notify(5)
+        self.message_sender.send('FSM', 'Entered state 5!')
-
-    def state_notify(self, state):
-        self.message_sender.send('TestFSM', f'Entered state {state}!')

solvable/src/test_fsm.yml

@@ -0,0 +1,43 @@
+# This defines an FSM equvivalent to test_fsm.py
+
+states:
+    -   name: '0'
+    -   name: '1'
+        on_enter: |
+            python3 -c "from tfwconnector import MessageSender; MessageSender().send('FSM', 'Entered state 1!')"
+    -   name: '2'
+        on_enter: |
+            file=/home/user/workdir/cat.txt
+            echo "As you can see it is possible to execute arbitrary shell commands here." >> $file
+            python3 -c \
+            "
+            from tfwconnector import MessageSender
+            MessageSender().send('FSM', 'Entered state 2! Written stuff to $file')
+            "
+    -   name: '3'
+        on_enter: |
+            python3 -c "from tfwconnector import MessageSender; MessageSender().send('FSM', 'Entered state 3!')"
+    -   name: '4'
+        on_enter: |
+            python3 -c "from tfwconnector import MessageSender; MessageSender().send('FSM', 'Entered state 4!')"
+    -   name: '5'
+        on_enter: |
+            python3 -c "from tfwconnector import MessageSender; MessageSender().send('FSM', 'Entered state 5!')"
+transitions:
+    -   trigger: step_1
+        source: '0'
+        dest: '1'
+    -   trigger: step_2
+        source: '1'      
+        dest: '2'
+    -   trigger: step_3
+        source: '2'
+        dest: '3'
+        predicates:
+            - '[ -f /home/user/workdir/allow_step_3 ]'  # in bash -f means that the file exists
+    -   trigger: step_4
+        source: '3'
+        dest: '4'
+    -   trigger: step_5
+        source: '4'
+        dest: '5'